Actuating mechanism for a limit switch having elongated pivotally mounted actuating member

ABSTRACT

A switch actuating mechanism for an electrical limit switch. The actuating mechanism includes an actuating arm pivotally mounted at its upper end on the limit switch in interferring relation to the switch mechanism of the limit switch. When the actuating arm is contacted by a moving object, such as the carriage of a machine or the like, the actuating arm is pivoted into the switch mechanism operating the limit switch. As the object moves away from the actuating arm, the arm pivots downwardly, by the force of gravity, back to a neutral or centered position.

United States Patent 1191 Carpenter et al.

ACTUATING MECHANISM FOR A LIMIT SWITCH HAVING ELONGATED PIVOTALLY MOUNTED ACTUATING MEMBER Inventors: Loyde M. Carpenter, Hickory;

James W. Kiser, Iron Station; Lee V. Leonard, Hickory, all of N.C.

General Electric Company, Pittsfield, Mass.

Filed: May 26, 1972 Appl. No.: 257,291

Assignee:

US. Cl 200/172 A, 200/47, ZOO/61.41 Int. Cl. .L H0lh 3/16 Field of Search.. ZOO/172 A, 153 K, 153 T, 47,

ZOO/61.41, 61.13

References Cited UNITED STATES PATENTS Grover ZOO/61.13

[ Jan. 29, 1974 3,207,870 9/1965 Herrera et al. ZOO/61.41 3,197,620 7/1965 Peltier 200/61.41 x 3,175,057 3/1965 Winslow 200/6l.4l 3,649,780 3/1972 'Johnson 200/1 v 3,649,785 3/1972 Dietrich 200/47 Primary Examiner-Robert K. Schaefer Assistant Examiner-William J. Smith Attorney, Agent, or Firm-Francis X. Doyle [5 7] ABSTRACT A switch actuating mechanism for an electrical limit switch. The actuating mechanism includes an actuating arm pivotally mounted at its upper end on the limit switch in interferring relation to the switch mechanism of the limit switch. When the actuating arm is contacted by a moving object, such as the carriage of a machine or the like, the actuating arm is pivoted into the switch mechanism operating the limit switch. As the object moves away from the actuating arm, the arm pivots downwardly, by the force of gravity, back to a neutral or centered position.

3 Claims, 3 Drawing Figures PAIENTEI] JAN 2 9 I974 ACTUATING MECHANISM FOR A LIMIT SWITCH HAVING ELONGATED PIVOTALLY MOUNTED ACTUATING MEMBER BACKGROUND This invention relates to actuating mechanisms and more particularly to a switch actuating mechanism for actuating a limit switch.

As is well known to those skilled in this art, limit switches are used in many types of apparatus to complete or to interrupt an electrical connection. For example, they are often used in machines to limit the movement of the machine carriage, or an operating tool. As is understood, when the carriage completes a traverse, the limit switch is contacted completing an electrical circuit to stop the motion of the carriage and often to reverse its motion, causing it to traverse in the opposite direction. Of course, after the limit switch has been operated, it is required that-the switch or actuating mechanism return to its neutral or centered position.

In most prior art devices, cams, springs or rachets, or

a combination of these devices is used to return the actuating mechanism to its centered or at rest position. In many of these prior art devices, the springs often break, and also require periodic adjustment due to the change in spring tension over a period of time and use. Also, it occasionally happens that the limit switch is operated twice for one movement of the actuating mechanism because of the action of the spring in returning the actuating mechanism to its normal or at rest position. Obviously, there is a'need in the limit switch art for an actuating mechanism which does not require the use of springs, cams, rachets or the like.

It is, therefore, a principal object of this invention to provide a limit switch actuating mechanism which does not require the use of springs or the like.

A further object of this invention is to provide a limit switch actuating mechanism which relies on the force of gravity to return the actuating mechanism to its normal or at rest position.

Yet another object of this invention is to provide a novel limit switch actuating mechanism that is pivotally mounted on the limit switch and is suspended downwardly from such switch in its normal or at rest position without the use of springs, cams or the like.

SUMMARY Briefly, in one form this invention comprises an actuating mechanism for a limitswitch. The actuating mechanism is pivotally mounted at its upper end to the limit switch and is suspended downwardly by the force of gravity. The actuating mechanism is in interferring relation with the switch operator of the limit switch such that pivotal movement of the actuating mechanism contacts the switch operator to thus operate the limit switch. The actuating mechanism then returns to its normal position by the force of gravity.

The invention which is sought to be protected will be particularly pointed out and distinctly claimed in the claims which are appended hereto. However, it is believed that the invention and the manner in which its various objects and advantages are obtained, as well as other objects and advantages thereof will be better understood by reference to the following detailed description of a preferred embodiment thereof, particularly when considered in connection with the accompanying drawing.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a front view of a limit switch and a preferred form of the actuating mechanism of this invention;

FIG. 2 is a side view of the apparatus shown in FIG. 1; and

FIG. 3 is a modified form of the actuating mechanism shown in FIGS. 1 and 2.

DESCRIPTION OF PREFERRED EMBODIMENT The actuating mechanism of this invention is shown in conjunction with a standard limit switch that is well known to those skilled in this art. It will, of course, be obvious that such actuating mechanism can be used with any type of limit switch. The preferred embodiment will be described with reference to the drawings, in which like numerals are used to indicate like parts throughout the various views.

Referring first to FIGS. 1 and 2, a limit switch 10 is shown having a switch operator 12, which may be provided with a roller 14, at the end thereof, as shown. As will be understood, limit switch 10 is provided with normally opened or normally closed contacts. Movement of switch operator 12 causes such contacts to close, or open, according to the type of switch. No further description will be provided of limit switch 10 and operator 12, since they are well known in the art, and form no part of this invention.

In one preferred embodiment, limit switch 10 is mounted on mounting plate 16, by means of screws 18. The mounting plate 16 may be attached to any type of machine or other apparatus (not shown) with which the switch 10 is to be used. As is shown in FIGS. 1 and 2, a mounting bolt or shaft 20 is secured to plate 16 in any desired manner, such as by welding. Shaft or bolt 20 is mounted near switch operator 12, as shown. A tube member 22 is provided, sliding over bolt 20. Bolt 20 is threaded at its outer end and nut 24 is threaded thereon to hold tube 22 in place on bolt 20. As will be apparent, this pivotally mounts tube 22 on bolt 20.

An arm member 26 is welded, or otherwise secured to tube 22 and hangs downwardly, as shown. In the preferred embodiment shown in FIGS. 1 and 2, a substantially right angled member 28 is secured to the lower end of arm 26. As will be understood, arm 26 and angled part 28 are pivotally suspended from bolt or shaft 20 by means of tube 22. The switch operator 12 is beside shaft 20 and in interferring relation with arm 26. As a moving object (not shown), such as a machine carriage, engages arm 26 or member 28, from the right as viewed in FIG. 1, arm 26 will be pivoted in a clock wise direction about shaft 20. As will be apparent, arm 26 will engage roller 14, thereby moving switch operator 12 to operate limit switch 10. After the limit switch 10 has operated and the object (not shown) has moved away from arm 26, the force of gravity will return arm 26 to the normal or at rest position shown in the draw- FIG. 3 shows an enlarged view, partially in section, of a slightly modified actuating mechanism. The tube 22, shaft or bolt 20, threaded end and nut 24 are the same as shown in FIGS. 1 and 2. As will be clear from FIG. 3, tube 22 is slightly larger in inner diameter than the outer diameter of shaft 20, so as to pivot freely thereon. The opposite end of bolt or shaft 20 is shown as provided with head 30, which may be used to weld bolt 20 to mounting plate 16. The arm 26 is a single member welded to tube 22 and extending downwardly therefrom.

It will be apparent that any configuration of arm 26 or 26' may be used, as long as it is positioned to move switch operator 12 to operate switch when it is pivoted through a sufficient angle about shaft 20. Of course, arm 26, 28; or 26 must be placed so as to be engaged by a moving object tovcause operation of the limit switch 10.

While there has been shown and described the present preferred embodiment of this invention, it will be apparent that various changes may be made by those skilled in this art without departing from the spirit or scope of the invention as defined in the appended claims.

We claim:

1. A switch actuating mechanism for a limit switch, which switch is provided with an operating member, said actuating mechanism comprising a bolt member fixedly mounted adjacent said limit switch, an elongated arm, said elongated arm being pivotally mounted at its upper end to said bolt member, a portion of said operating member extending below said bolt member for engagement by a portion of said elongated arm below said upper end, said elongated arm being pivotable into contact with the operating member, gravity maintaining said elongated arm in a neutral position out of engagement with said operating member with the lower end of said elongated arm below said upper end.

2. A switch operating mechanism as set forth in claim 1 in which said upper end of said elongated arm is provided with a tube member, said tube member surrounding said bolt.

3. A switch operating mechanism as set forth in claim 1 in which said lower end of said elongated arm has secured thereto a member substantially at a right angle thereto. 

1. A switch actuating mechanism for a limit switch, which switch is provided with an operating member, said actuating mechanism comprising a bolt member fixedly mounted adjacent said limit switch, an elongated arm, said elongated arm being pivotally mounted at its upper end to said bolt member, a portion of said operating member extending below said bolt member for engagement by a portion of said elongated arm below said upper end, said elongated arm being pivotable into contact with the operating member, gravity maintaining said elongated arm in a neutral position out of engagement with said operating member with the lower end of said elongated arm below said upper end.
 2. A switch operating mechanism as set forth in claim 1 in which said upper end of said elongated arm is provided with a tube member, said tube member surrounding said bolt.
 3. A switch operating mechanism as set forth in claim 1 in which said lower end of said elongated arm has secured thereto a member substantially at a right angle thereto. 